Beyond the emissions footprint the most surprising, and altogether unintuitive, result was that vertical farms had a greater land-use impact than field farms. This came down to the roots of the plants—literally. In vertical farms, lettuce plants are often sown in natural casings made of jute fibers, which come from a tall grass crop that’s cultivated in tropical regions.

Is it jute, or is it grass? You cannot have it both ways. (In either case, coconut coir or a sustainable non-timber forest product would definitely make more sense for large-scale deployments.)